Hydrocarbon conversion process



United States Patent "ice 3,18%997 HYDRQCARBGN CONVERSEON PROCESS Harry M. Brennan, Hammond, John R. Coley, Gary, Clifton G. Frye, Valparaiso, and Louis C. Gutheriet, Cedar Lake, ind, assignors to Standard Oil tflornpany, Chicago, llll., a corporation of Indiana No Drawing. Filed May 31, 1961, Ser. No. 113,624 13 Claims. (Ci. 260-63355) This invention relates to the production of branchedchain parafiinic hydrocarbons. More particularly, the

.invention relates to a process for producing isoparafiins from normal olefins or from hydrocarbon mixtures containing substantial amounts of normal olefins by contacting such olefinic materials with a particular composite catalyst having critically balanced isomerization and hydrogenation activities.

Light isoparafiins, i.e., those boiling within the gasoline boiling range, have markedly higher leaded motor octane ratings than either olefins of the same carbon number or the corresponding normal paraffins. Also, there has evidenced a trend to limit the amount of olefins in gasoline, at least in certain geographic areas. Therefore, there is a definite advantage for saturating the olefins in refinery streams such as light cracked naphtha, and a further advantage results from converting the normal bydrocarbons in such streams to branched-chain hydrocarbons.

Generally, processes employing multifunctional catalysts having hydrogenation activities and isomerization activities have not been capable of producing greater than thermodynamic equilibrium concentrations of isoparaffins from normal olefins, or else have not been capable of providing a substantial saturated product. Other processes for producing isoparaffins from normal olefins have employed catalysts which upon becoming (le-ElCllVEllBd in use, involve a ditiicult and complex regeneration technique. I

It has now been found that if a relatively small amount of an activity control-affording substance is incorporated in a composite catalyst having balanced isomerization and hydrogenation activities under the conditions of the process, normal olefin-s can be converted to a product containing more branched-chain paratlins than the parafiin isomerization equilibrium amount at the operating temperature, and'high yields, i.e., up to about 95%, of isoparaffins can be produced. Further, after becoming deactivated these catalysts are readily regenerable by a simple technique.

Briefly, the present invention provides a process for producing high yields of isoparaflins from normal olefins which process comprises contacting an olefinic hydrocarbon in a reaction zone with a catalyst in the presence of a hydrogen-aiiording gas under isomerization-hydrogenation conditions, said catalyst being a composite catalyst comprising a metallic hydrogenation component, a solid acidic component and from about 0.03 to 5 atoms of a metal selected from the group consisting of copper, lead, silver and mercury per atom of said hydrogenation component. i

In a preferred embodiment of the invention, the above mentioned process employs a catalyst comprising a Group VIII hydrogenation component, particularly nickel, platinum, palladium or cobalt and from about 0.1 to 2 atoms of a metal selected from the group consisting of mercury, lead and copper per atom of said Group VH1 metal supported on a silica-alumina cracking catalyst base.

In the process of the invention, an olefinic hydrocarbon stream, which may be a substantially pure olefin or a hydrocarbon mixture having substantial olefin content, preferably about 50 percent or more olefins, is selected as a 3,l82,@9l Patented May 4, 1965 feed. Refinery streams particularly suitable as feed stocks for the process are light olefinic naphthas boiling in the range from about 20 F. to about 350 F., and, especially, light thermal or catalytic cracked naphthas containing substantial quantities of normal olefins having a carbon number distribution in the range from about C to C Advantageously, a narrow cut of such naphthas containing substantial quantities of C -C normal olefins, and most preferably a C -C olefinic fraction is employed since this latter fraction is unusually well adapted as a feed for the process. The olefinic feed stock may be derived from petroleum, shale, gilsonite or other suchorganic materials.

The olefinic feed is introduced into areaction zone Where it is contacted with the catalyst in the presence of at least sufiicient hydrogen for olefin saturation. The operation may be liquid phase, vapor phase, or mixed liquid-vapor phase. Advantageously, a hydrogen-rich gas such as substantially'pure hydrogen, catalytic reformer make-gas or other gas streams containing available hydrogen for olefin saturation is introduced into the reaction zone with the feed. The minimum amount of hydrogen required will be the stoichiometric amount required for olefin saturation, and the amount of hydrogen will vary according to the nature of the feed stock. Preferably, an excess of hydrogen is employed, which in practice will usually be at least about 1500 s.c.f. per barrel of olefinic feed. Larger excesses of hydrogen or inert gases may be employed to reduce olefin partial pressure to increase the iso to normal (i/n) parafiin ratio of the converted product. p V

The reaction zone is operated under conditions promoting the isomerization-hydrogenation of olefins to iso paraffins. A superatmospheric pressure is employed, which pressure can range up to 3000 p.s.i.g. or more, but preferably is in the range of about to 1500 p.sli.g. An elevated temperature is employed in the catalyst bed, which temperature typically is in the range of about 400 F. to 750 F.,-and preferably is about 450 F. to 650 F. Catalystactivities, the nature of the material charged to the reaction zone, pressure and other operating variables will affect the selection of the operating temperature. Liquid hourly space velocities (LHSV) of from about 0.1 to 50 volumes of hydrocarbon (as liquid) per hour per volume of catalyst are employed, most generally about 0.1 to 10 LHSV, and with a preferred rate being about 1 to -10 LHSV.

In the manufacture of the catalyst employed in the present invention, a metallic hydrogenation component, such as the metals of Group VIII of the Periodic Table, particularly nickel, platinum, palladium and cobalt are incorporated in the catalyst composite. In a preferred embodiment of the invention, a Group VII hydrogenation metal supported on a silica-alumina cracking catalyst base is impregnated with mercury, lead or copper to provide a finished catalyst having the desired balance of the catalyst activities. While an impregnated type catalyst is preferred, other catalyst forms may be employed, such as a catalyst wherein the various components are co-precipitated from' a sol. Advantageously, the hydrogenation component can be incorporated into the catalyst by impregnatingthe solid acidic support with various solutions of the hydrogenation metal group, such as palladium chloride, chloroplatinic acid, nickel acetate, nickel nitrate,retc., followed by drying and calcining at elevated temperature.

The amount of the hydrogenation component incorporated in the catalyst can vary over a wide range, with the amount being selected to provide the. desired catalyst activity. For example, large amounts of nickel, e.g., up to. about 30 weight percent can be employed, and as little as about 0.1 Weight percent is also effective, with about 0.5 to 5 weight percent nickel being preferred. Typically, about 0.1 to 2 weight percent platinum has likewise been found to be very effective, and preferably about 0.1 to 1 weight percent platinum is employed.

In general, the acidic component of the catalyst must provide suflicient acidity to promote the skeletal isomerization of straight chain olefins under the conditions of the process, and a porous, high surface area material of about 100-500 square meters per gram preferably is employed. On the other hand, the acidity should not be such as to promote the rapid isomerization of paraffins. Methods of measuring catalyst acidity are well known and need not be described herein. Typically, the solid acidic component of the catalyst can be a naturally occurring mineral such as montmorillonite clay, a synthetic silica-alumina, or a combination of these. Preferably, an artificial aluminosilicate, such as one of the commercially available silicaalumina cracking catalysts is utilized as a support. These cracking catalysts are made by co-precipitating alumina and silica sols. The alumina portion of the support may vary from about 5 to about 40 weight percent. Both the commercially available high-alumina silica-alumina cracking catalyst containing about 20-30 weight percent A1 and the low alumina material containing about 10-15 weight percent A1 0 are effective as the acidic component of the present catalyst.

It is necessary to incorporate a sufiicient amount of mercury, lead or copper ino the catalyst to achieve the proper balance of catalyst activities. Overly large quantities of these elements will reduce the hydrogenation activity to the point where a desirable degree of saturation cannot be obtained, while insufiicient amounts may result in a too rapid rate of hydrogenation compared to the rate of isomerization so that the desired concentration of isoparafiins, i.e., a low i/n parafiin ratio, is obtained. Normally, only small amounts of mercury, lead or copper need be incorporated in the catalyst and these elements can be employed either singly or in combination. The total amount required will be dependent upon the total amount of hydrogenation metal incorporated in the catalyst and upon its chemical form. Typically, a 5 weight percent nickel catalyst having from about 1 to 20 weight percent mercury, silver or lead is employed, while from about 1 to Weight percent copper can be employed. Broadly, about 0.03 to 5 atoms of copper, lead or mercury per atom of the hydrogenation component metal may be incorporated in the catalyst, optimally about 0.05 to 2, and preferably about 0.1 to 1 atoms of such elements per atom of the hydrogenation metal is employed.

Preferably, the desired proportion of mercury, lead, silver or copper is incorporated in the catalyst during its manufacture. For example, a nickel on silica-alumina catalyst base can be impregnated with a solution of an organic compound, including the aryl or alkyl substituted organometallics, the solvent evaporated and the organic compound reduced to leave a deposit on the silica-alumina base. Also, the catalyst base can be impregnated with soluble inorganic compounds of mercury, lead, silver and copper, with subsequent drying, calcination and reduction of the catalyst by hydrogen. Salts of the above types which are particularly well-suited for this purpose are the nitrates and acetates of the above-mentioned elements. Also, such solutions as mentioned may be introduced into the reaction zone to contact the catalyst base in situ, as by additions to the feed charged to the reactor, and thereby incorporate the desired element into the catalyst.

A particular advantage of the catalyst in the process of the invention is that once the desired catalyst'composition is obtained there is little tendency under the operating conditions of the process for the catalyst composition to be altered and thereby lose control of the critical activity balance. Consequently, it is not necessary under normal conditions to maintain the above-mentioned additions in the feed.

After a period of operation wherein the catalyst is contacted with the hydrocarbon feed the catalyst activity may decline and carbonaceous deposits may accumulate on the catalyst. Olefin breakthrough, i.e., the appearance of unsaturates in the reactor eflluent, indicates the effective on-stream cycle length for the catalyst. When olefin break-through occurs, the catalyst may be regenerated to restore its activity to permit the production of a saturated product having a high i/n paraflin ratio again. A preferred regeneration technique comprises: oxidizing the carbonaceous deposits on the catalyst, preferably by employing a first dilute oxygen treatment followed by a second atmospheric air treatment, both at elevated temperatures; followed by reducing the catalyst as with hydrogen or a hydrogen-rich gas. It may be desirable to also treat the catalyst with hydrogen at elevated temperature prior to the oxidizing step to insure repeated reactivation for a number of regenerations.

It is to be understood that the above-mentioned activitycontrol-affording elements may be present in the catalyst in various chemical forms so as to effect the desired balance of catalyst activities, although the forms are not necessarily equivalent. As used herein, the term hydrogenation component refers to a catalyst constituent imparting hydrogenation activity to the catalyst under the conditions of the process. A number of hydrogenationactive catalysts have been used for this purpose, such as the metals and/ or oxides and other compounds of metals of Groups V and VI of the Periodic Table, and particularly, the hydrogenation-active metals of Group VIII of the Periodic Table, such as nickel, platinum, palladium, cobalt, osmium, iridium, rhodium and ruthenium.

The following examples are given for the purpose of illustrating the process of the present invention. However, it is to be understood that these examples are given by way of exemplification only and do not serve in any way to limit the scope of the invention.

COMPARISON TEST The following data is given as a basis for comparing the effectiveness of the catalyst employed in the present invention with an unbalanced catalyst consisting, typically, of nickel on silica-alumina.

A 5 weight percent nickel on silica-alumina catalyst was prepared by impregnating a 25 percent A1 0 silicaalumina cracking catalyst base with an aqueous solution of nickel acetate. The impregnated material was dried at 400 F. and calcined for 6 hours at 1000 F. The catalyst was then diluted with quartz and reduced in flowing hydrogen for 1 hour at 700 F. The finished catalyst was contacted in a reactor with pentene-2 at 574 F, 1000 p.s.i.g., 8.6 volumes of oil per hour per volume of catalyst and 9.7 moles of hydrogen per mole of hydrocarbon. The reactor eflluent was percent saturated and gas chromatography analysis indicated that the i/n C paraffin ratio was about 1.3.

Example I 25 gr. of powdered 5 weight percent nickel on high alumina silica-alumina cracking catalyst, prepared as described above, was impregnated with 40 cc. of an aqueous solution containing 0.40 gr. Hg(NO dried at 400 F. and calcined 4 hours at 1000 F. The finished catalyst contained 0.0048 mole of mercury per 100 grams of catalyst, or approximately 1 Weight percent mercury. The catalyst was then contacted in a reactor with pentene- 2 at 584 F., 1000 p.s.i. g., a hydrogen to hydrocarbon mole ratio of 10 and a liquid hourly space velocity of 10 volumes of oil per hour per volume of catalyst. The resulting C product in the reactor eflluent was 100 percent saturated and the i/n C paraffin ratio was 2.3.

Example 11 25 gr. of a catalyst was prepared as described in Example I except that 40 cc. nitrate solution containing for psi

25 gr. of percent nickel on silica-alumina catalyst base was prepared as described above and impregnated with 40 cc. of an aqueous solution containing 0.40 gr. Pb(NO followed by drying at 400 F. and calcining for 4 hours at 1000 F. The finished catalyst contained 0.0048 mole of lead per 100 grams of catalyst, oiapproximately 1 weight percent lead. The finished catalyst was contacted in a reactor with pentene-2 at 578 F., 1000 p.s.i.g., a hydrogen to hydrocarbon mole ratio of 10, and a liquid hourly space velocity of volumes of oil per hour per volume of catalyst. The C product was 100 percent saturated and the i/n C parafiin ratio was 5.0.

Example V 25 gr. of a catalyst was prepared as described in Example III, except that 40 cc. nitrate solution containing 7.05 gr. -Pb(NO was employed and the finished catalyst contained approximately 17.6 weight percent lead. The finished catalyst was contacted in a reactor with pentene- 2 at 579 -F., 1000 p.s.i.g., a hydrogen to hydrocarbon mole ratio of 10, a liquid hourly space velocity of 10 volumes of oil per hour per volume of catalyst. The resulting C product was 16.3 percent saturated and the i/n C parafiin ratio was 4.6.

Example V 125 gr. of 5 percent nickel on high alumina silicaalumina cracking catalyst base was prepared as previously described and this was impregnated with 40 cc. of an aqueous solution containing 0.95 gr. Cu('NO -3H O, followed by drying at 400 F. and calcining for 4 hours at 1000 F. The finished catalyst contained 0.0156 mole of copper per 100 grams of catalyst, or approximately 1 Weight percent copper. The catalyst was contacted in a reactor with pentene-2 at 581 F., 1000 p.s.i.g., a hydrogen to hydrocarbon mole ratio of 10, and a liquid hourly space velocity of 10 volumes of oil per hour per volume of catalyst. The resulting C product was found to be 9.6 percent saturated and the i/n C parafiin ratio was 3.

Example VI 25 gr. of a catalyst was prepared as described above in Example V except that 40 cc. nitrate solution containing 5.15 gr. Cu(NO -:3H O was employed and the finished catalyst contained 0.085 mole or" copper per 100 grams of catalyst, or approximately 5.4 weight percent copper. The catalyst was contacted in a reactor with pen tene-2 at 585 F., 1000 p.s.i.g., a hydrogen to hydrocarbon mole ratio of 10, a liquid hourly space velocity of 10 volumes of oil per hour per volume of catalyst. The resulting C product was found to be 90.6 percent saturated and the i/n C parafiin ratio was 7.0.

Example VII 25 gr. of 5 percent nickel on high alumina silicaalumina cracking catalyst base was prepared as previously described and this was impregnated with 40 cc. of aqueous nitrate solution containing 3.62 grams of AgNO followed by drying at 400 F. and calcining for 4 hours at 1000 F. The finished catalyst contained 0.085 mole of silver per 100 grams of catalyst, or approximately 9.2 weight percent silver. The catalyst was contacted in a reactor with pentene-2 at 590 :F., 1000 p.s.i.g., a hydrogen to hydrocarbon mole ratio of 10 and a liquid hourly space velocity of 10 volumes of oil per hour per volume of catalyst.

'0 The resulting C5 product was found to be 100 percent saturated and the i/n C parafiin ratio was 5.5.

In each of the foregoing examples the catalyst was reduced in flowing hydrogen for 1 hour at 700 F. and diluted with quartz prior to contacting the catalyst with the hydrocarbon.

The relative selectivity, i.e'., the amount of C isoparaffins produced at the particular degree of conversion obtained in that run compared to the product obtained with the catalyst of the comparison test (which is given a selectivity factor of 1), was determined for each catalyst in the examples. These relative selectivities then are indicativeof the ability of the catalyst to convert normal olefins to isoparaffins, and these'are as follows:

Catalyst: Relative selectivity 1% Hg5% NiSi/A1 1.7 17% Hg-'5% NiSi/Al 6.7 1% r p-5% NiSi/Al 3.7 17% Pb5% Ni-Si/Al 6.2 1% Cu5% Ni-Si/Al 2.3 5% -cu s% Ni-Si/Al 5.3 9% Ag5% NiSi/Al 4.0

From the foregoing description of the present invention various modifications and variations in the catalyst and methods of operation will become apparent to the skilled artisan,'which fall within the spirit and scope of the invention.

What is claimed is:

1. A process for the production of branched-chain para'i'finic hydrocarbons which process comprises contacting an olefinic hydrocarbon in a reaction zone with a catalyst in the presence of a hydrogen-affording gas under isomerization-hydnogenation conditions, including a temperature between about 400 F. and about 750 F., said catalyst being a composite catalyst which comprises a metallic hydrogenation component, a solid acidic component consisting essentially of a porous, high surface area material having suificient acidity to promote isomerization of parafiins and which is selected from the group consisting of mineral clays containing silica and alumina and synthetic silica-aluminas and from 0.03 to 5 atoms of a metal selected from the group consisting of copper,

- lead, silver and mercury per atom of said hydrogenation component.

2. The process of claim 1 wherein said hydrogenation component is a Group VIII hydrogenation-active metal. 3. The process of claim 1 wherein said solid acidic component is synthetic silica-alumina.

4. The process of claim 1 wherein said isomerizationhydrogenation conditions include a temperature of about 400 F. to 750 R, an elevated pressure, a liquid hourly space velocity of about 0.1 to 50 volumes of hydrocarbon per hour per volume of catalyst, and wherein an excess of hydrogen over the stoichiometric amount required for olefin saturation is employed.

5. The process of claim 1 wherein said olefinic hydrocarbon is a light naphtha fraction containing substantial C -C normal olefins.

6. The process of claim 1 wherein said copper, mercury, silver and lead are present in an amount between about 0.1 to 1 atom per'atom of said hydrogenation component.

7. A process for the production of branched-chain paraffinic hydrocarbons which process comprises contacting an olefinic hydrocarbon in a reaction zone in the presence of a hydrogen-affording gas with a catalyst comprising a Group VIII hydrogenation metal and from about 0.05 to 2 atoms of a metal selected from the group consisting of copper, lead, silver and mercury per atom of said Group VIII metal supported on silica-alumina under conditions which include a temperature in the range of about 400 F. to 750 F, a pressure in the range of about to 1500 p.s.i.g., and a liquid hourly space velocity in the range of about 0.1 to 50 volumes of hydrocarbon per hour per volume of catalyst.

8. The process of claim 7 wherein said hydrogenation metal is nickel.

9. The process of claim 7 'wherein said hydrogenation metal is platinum.

10. The process of claim 7 wherein said conditions include a temperature in the range of about 450 F. to 650 F., a liquid hourly space velocity ofabout 1 to 10 volumes of hydrocarbon per hour per volume of catalyst, and at least about 1500 standard cubic feet of hydrogen per barrel of olefin are employed.

11. The process of claim 7 wherein said copper, lead, silver and mercury is present in an amount between about 0.1 to 1 atom per atom of said Group VIII metal.

12. The process of claim 7 wherein said olefinic hydrocarbon is a light naphtha fraction containing substantial C C normal olefins.

13. A process for the production of branched-chain paratfinic hydrocarbons which comprises contacting a C -C normal olefinic hydrocarbon with a catalyst con prising about 0.5 to weight percent nickel and from 0.1 to 1 atom of a metal selected from the group consisting of copper, lead, silver and mercury per atom of said nickel supported on a silica-alumina cracking component in the presence of at least about 1500 standard cubic feet of hydrogen per barrel of said olefins and at a temperature in the range of about 450 F. to 650 F., a pressure in the range of about to 1500 p.s.i.g., and a liquid hourly space velocity of between about 1 to 10 volumes of oil per hour per volume of catalyst.

References Eited by the Examiner UNITED STATES PATENTS 2,538,248 1/51 Ipatietf et al. 260-6832 2,911,357 11/59 Myers et al. 208-138 2,943,996 7/60 Watkins 208 3,003,952 10/61 Cramer et al 208138 FOREIGN PATENTS 555,861 9/43 Great Britain.

OTHER REFERENCES Emmett: Catalysis, vol. IV, Reinhold Publishing Corporation (1956), page 513 relied upon.

ALPHONSO D. SULLIVAN, Primary Examiner. 

1. A PROCESS FOR THE PRODUCTION OF BRANCHED-CHAIN PARAFFINIC HYDROCARBONS WHICH PROCESS COMPRISES CONTACTING AN OLEFINIC HYDROCARBON IN A REACTION ZONE WITH A CATALYST IN THE PRESENCE OF A HYDROGEN-AFFORDING GAS UNDER ISOMERIZATION-HYDROGENATION CONDITIONS, INCLUDING A TEMPERATURE BETWEEN ABOUT 400*F. AND ABOUT 750*F., SAID CATALYST BEING A COMPOSITE CATALYST WHICH COMPRISES A METALLIC HYDROGENATION COMPONENT, A SOLID ACIDIC COMPONENT CONSISTING ESSENTIALLY OF A POROUS, HIGH SURFACE AREA MATERIAL HAVING SUFFICIENT ACIDITY TO PROMOTE ISOMERIZATION OF PARAFFINS AND WHICH IS SELECTED FROM THE GROUP CONSISTING OF MINERAL CLAYS CONTAINING SILICA AND ALUMINA AND SYNTHETIC SILICA-ALUMINAS AND FROM 0.03 TO 5 ATOMS OF A METAL SELECTED FROM THE GROUP CONSISTING OF COPPER, LEAD, SILVER AND MERCURY PER ATOM OF SAID HYDROGENATION COMPONENT. 